<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>

  <input type="button" value="播放">
  <script>
    let input = document.querySelector('input');
    input.onclick = function(){
      if(input.value == '播放' ){
        input.value = '暂停';
      }else if(input.value == '暂停'){
        input.value = '播放';
      }
    }

  </script>
  
</body>
</html>